This invention relates, in general, to optical devices and, more particularly, to optical waveguides.
At present, optical signals are transmitted through interconnections called waveguides. Typically, these waveguides interconnect photonic devices, such as light emitters and light detectors.
Conventionally, optical signals or light beams in polymer waveguides are split or directed into parts by beam splitting or Y-branching components.
Typically, beam splitting requires completely sectioning or terminating a first waveguide at an angle. A partially reflective surface or mirror is positioned at the angle of the terminated end of the first waveguide. Subsequently, a second waveguide is positioned at the partially reflective mirror. A light signal passing through the first waveguide encounters the partially reflective mirror and reflects part of the light signal at an oblique angle, while another part is passed through the partially reflective mirror into the second waveguide. However, fabrication of beam splitters in this manner presents several problems, such as complexity of fabrication, cost of fabrication, and inherent losses in light signals meeting interfaces
Y-branching of optical signals is achieved by dividing a single waveguide into two parts in a form of a Y. However, use of Y-branching has several problems, such as requiring a large footprint or a large area to construct and poor control of splitting a specific amount or portion of the optical signal or light. These problems makes Y-branching inappropriate as an inexpensive and manufacturable method for splitting light.
U.S. Pat. No. 4,772,787 by Trommer et al. and U.S. Pat. No. 4,756,590 by Forrest et al. both teach methods of total reflection of light traveling through a waveguide composed of III-V materials or an optical fiber respectively. Neither Trommer et al. nor Forrest et al. solve the problem of partial diversion or partial collection of light from a polymer waveguide. Additionally, it is known in the art that scratching or nicking optical fibers enables light to escape from the scratch or nick; however, scratching or nicking the optical fiber can break the optical fiber, thereby not providing a solution to enable light to be coupled out of the optical fiber in a controlled manner.
It can be readily seen that conventional light-signal splitting methods in waveguides have severe limitations in reliable fabrication. Additionally, it is also evident that manufacturing complexity and efficiency of light-signal coupling are also limited. Therefore, a method for making an optical partial collector simply, effectively, and with greater efficiency would be highly desirable.